ltc5100 Linear Technology Corporation, ltc5100 Datasheet - Page 27

• Manufacturer Part Number: ltc5100
• Description: 3.3v, 3.2gbps Vcsel Driver
• Manufacturer: Linear Technology Corporation

OPERATIO
by an on-chip temperature sensor or by an external
microprocessor, according to the setting of Ext_temp_en.
The temperature compensated expression for Ib_set is
given by:
Ib_tc1 and Ib_tc2 are the first and second order tempera-
ture coefficients for the laser bias current.
Ib set Ib nom
_
Rapid_restart_en = 0
ENABLE AND
_
ENABLE = EN AND Soft_en
FAULT = Over_current OR
U
Rapid_restart_en = 1
Operating_mode = 1
TIMEOUT
SUCCEEDED OR
40ms
•
POWER ON RESET OR
TIMEOUT
ENABLE AND
Over_power OR
Under_power
Operating_mode = 0
ENABLE
ENABLE
100ms
Ib tc
1
2
4
5
6
7
Ib tc
_
(DISABLED)
(ENABLED)
(ENABLED)
DISABLED)
(ENABLED)
SETTLING
(SETTLED
SETTLING
SETTLED
EEPROM
Figure 27. State Diagram for Transmitter Enable and Fault Detection
_
READY
READY
READ
AND
2 2
•
1 2
•
–
18
ENABLE
ENABLE
–
FAULT DETECTION DISABLED
Transmitter_enabled = 1
Transmitter_enabled = 0
Transmit_ready = 0
FAULT DETECTION DISABLED
Transmit_ready = 1
FAULT
FAILED
Mem_load_error = 1
Transmitter_enabled = 0
13
FAULT DETECTION ENABLED
Transmit_ready = 1
•
•
T
2
T
1
TIMEOUT
Faulted_once = 0
(29)
WAIT
64ms
Operating_mode = 1
TIMEOUT
TRANSMIT ENABLE, FAULT DETECTION
AND EYE SAFETY
The LTC5100 is compatible with the Gigabit Interface
Converter (GBIC) specification, but includes additional
features and safety interlocks. Figure 27 shows the state
diagram for enabling the transmitter and detecting faults.
The EN pin and Soft_en control bit enable and disable the
transmitter. The EN pin may be programmed for active
high or active low operation with the En_polarity bit.
Rep_flt_inhibit = 0
Rep_flt_inhibit = 1
25ms
3
ENABLE AND
ENABLE AND
ENABLE
10
11
12
8
9
FAULT
(DISABLED)
(DISABLED)
(DISABLED)
(ENABLED)
(ENABLED)
SETTLING
SETTLING
FAULTED
FAULTED
READY
TWICE
100ms
TIMEOUT
ENABLE
FAULT PIN ASSERTED
Transmitter_enabled = 0
Transmit_ready = 0
Faulted = 1
Faulted = 0
Faulted_once = 1
FAULT DETECTION DISABLED
Transmitter_enabled = 1
FAULT DETECTION ENABLED
Transmit_ready = 1
POWER ON RESET
Faulted = 1
Faulted_once = 1
Faulted_twice = 1
5100 F27
LTC5100
sn5100 5100fs
27